One way of electrically connecting the pads of an electronic component having closely spaced contact pads, to the pads of a circuit card, is to braze to each pad of the electronic component, the head of an electrical pin, using a gold alloy. The pins are then inserted into plated through holes in the circuit card and soldered to the plating of the holes. Alternatively the pins may be inserted into sockets which have been soldered into plated through holes in the circuit card. In the first case, it is inconvenient to remove the electronic component from the circuit card for diagnosis or replacement, and in the second case it is expensive to provide the sockets, which may be low insertion force sockets or zero insertion force sockets, and economy of space is not achieved. In any event, the brazing of the pins to the contact pads of the electronic component is both time consuming and expensive.
Another expedient, is to interpose between the electronic component and the circuit card, an electrical connector consisting of a glass-ceramic substrate with small cylindrical holes positioned in accordance with the grid array, each hole being stuffed with fine gold or gold-plated wires forming a resilient mesh which is known in the art as a "fuz button". Fuz buttons are expensive to provide in view of the amount of gold that must be used, and their construction is labor intensive. Also, such fuz buttons afford but low contact force and have no capability of wiping the pads that they are to connect, upon their engagement therewith.
There are disclosed in U.S. Pat. No. 4,511,197, U.S. Pat. No. 4,513,353, U.S. Pat. No. 4,647,124 and U.S. Pat. No. 4,699,593, electrical connectors of the type known as "interposer" connectors, such connectors comprising an insulating structure having cavities therein receiving electrical contact elements with contact noses each projecting from opposite interface surfaces of the structure. Such a connector is for interposition between an electronic component and a printed circuit card, so that each contact nose of each contact element engages with a respective pad of the electronic component and a respective pad of the circuit card. According to U.S. Pat. No. 4,513,353 the contact elements are retained in their cavities, by means of a contact retainer secured in position against the insulating structure, by means of a metal clamp. A similar means for retaining the contact elements in their cavities, being employed according to the teaching of U.S. Pat. No. 4,511,197 and U.S. Pat. No. 4,647,124 which teach that the contact elements are retained in their cavities by means of ears which project laterally from each contact element and are received in slots defined by L-shaped posts in the cavities, and by adjacent walls thereof. According to U.S. Pat. No. 4,699,593, the contact elements are inserted into slots formed in modules which are subsequently inserted into openings in a frame to retain the contact elements in their slots. None of these connectors is designed for use with an electronic component having contact pads distributed over its whole interface surface in a grid array.